#ifndef __PROCESS_POOL_HPP__
#define __PROCESS_POOL_HPP__


#include<iostream>
#include<cstdlib>
#include<vector>
#include<sys/wait.h>
#include<string>
#include<unistd.h>
#include"Task.hpp"

//先描述
class Channel{
public:
    Channel(int fd,pid_t id):_wfd(fd),_subid(id){
        _name = "channel-" + std::to_string(_wfd) + "-" + std::to_string(_subid);
    }
    ~Channel(){

    }
    
    void Sent(int code){
        int n = write(_wfd,&code,sizeof(code));
        (void)n;
    }

    void Close(){
        close(_wfd);
    }

    void Wait(){
        pid_t pid = waitpid(_subid,NULL,0); 
        (void)pid;
    }
    int Fd(){
        return _wfd;
    }

    pid_t SubId(){
        return _subid;
    }

    std::string Name(){
        return _name;
    }
private:
    int _wfd;
    pid_t _subid;
    std::string _name;
    //int _loadnum;
};

//再组织
class ChannelManager{
public:
    ChannelManager():_next(0){

    }

    void Insert(int wfd,pid_t subid){
        _channels.emplace_back(wfd, subid);
        //Channel c(wfd,subid);
        //_channels.push_back(c);
    }

    Channel &select(){
        auto &c = _channels[_next];
        _next++;
        _next %= _channels.size();
        return c;
    }

    void PrintChannel(){
        for(auto &channel : _channels){
            std::cout<<channel.Name()<<std::endl;
        }
    }

    void StopSubProcess(){
        for(auto &channel : _channels){
            channel.Close();
            std::cout<<"关闭信道"<<channel.Name()<<std::endl;
        }
    }

    void WaitSubProcess(){
        for(auto &channel : _channels){
            channel.Wait();
            std::cout<<"等待子进程"<<channel.Name()<<"结束"<<std::endl;
        }
        
    }

    ~ChannelManager(){

    }
private:
    std::vector<Channel> _channels;
    int _next;
};

const int gdefaultnum = 5;

class ProcessPool{
public:
    ProcessPool(int num):_process_num(num){
        _tm.Register(PrintLog);
        _tm.Register(DownLoad);
        _tm.Register(upload);  
    }

    void Work(int rfd){
        while(true){
            int code = 0;
            ssize_t n =read(rfd,&code,sizeof(code));
            if(n > 0){
                if(n != sizeof(code)){
                    continue;
                }
                std::cout<<"子进程["<<getpid()<<"]收到一个任务码:"<<code<<std::endl;
                _tm.Execute(code);
            }
            else if(n == 0){
                std::cout<<"子进程退出"<<std::endl;
                break;
            }
            else{
                std::cout<<"读管道失败"<<std::endl;
                break;
            }
        }
    }

    bool Start(){
        for(int i = 0; i < _process_num; i++){
            //1.创建管道
            int pipefd[2] = {0};
            int n = pipe(pipefd);
            if(n < 0) return false;
            
            //2.创建子进程
            pid_t subid = fork();
            if(subid < 0) return false;
            else if(subid == 0){

                //子进程
                //3.关闭不需要的文件描述符
                close(pipefd[1]);
                Work(pipefd[0]);
                close(pipefd[0]);
                exit(0);
            }
            else{
                //父进程
                //3.关闭不需要的文件描述符
                close(pipefd[0]);
                _cm.Insert(pipefd[1],subid);
            }

        }

        return true;
    }

    void Debug(){
        _cm.PrintChannel();
    }

    void Run(){
        //1.选择一个任务
        int taskcode = _tm.Code();
        //2.选择一个子进程（信道）负载均衡的选择一个进程，完成任务
        auto &c = _cm.select();
        std::cout<<"选择一个子进程："<<c.Name()<<std::endl; 
        //3.向进程发送任务
        c.Sent(taskcode); 
        std::cout<<"向子进程发送任务码："<<taskcode<<std::endl;
    }

    void Stop(){
        //关闭父进程的所有wfd即可
        _cm.StopSubProcess();
        //回收所有子进程
        _cm.WaitSubProcess();
    }

    ~ProcessPool(){

    }
private:
    ChannelManager _cm;
    int _process_num;
    TaskManager _tm;
};





#endif